Insulating leading-in conductor



Jan. 3, 1939. D. s. GUSTIN INSULATING LEADING-IN CONDUCTOR Filed April22, 1936 E N R 0 w A INVENTOR D. S. GUST/N 277 9 Patented Jan. 3, 1939UNITED STATES PATENT OFFICE INSULATING LEADING -IN CONDUCTOR ApplicationApril 22, 1936, Serial No. 75,745

2 Claims. (Cl. 176-126) My invention relates to electric vapor dischargelamps and particularly to the leading-1n conductors therefor whichsupply electrical energy to at least one of the electrodes.

Lamps of this general type are well known to the art wherein a dischargeoccurs between two spaced electrodes due to ionization of a vaporizablematerial, such for example, as mercury. Because of the necessity for asubstantial spacing between the electrodes they are normally disposed atopposite ends of a tubular envelope. Also in order to render the lampreadily adaptable to the usual commercial socket it has been customaryto supply electrical energy to the re- '15 spective electrodes throughsuitable leading-in conductors which are sealed through the glass wallof the envelope at one end of the envelope where they are connected tothe threaded base of the lamp.

This accordingly necessitates one of the leading-in conductors extendinglongitudinally of the envelope from the end provided with the threadedbase to the oppositely disposed electrode and in order to preventoxidation or severance of the conductor it is usually disposedinternally of the envelope. To prevent a discharge from the leading-inconductor to the electrode carrying opposite instantaneous polarity ithas been customary to insulate the portion of the leading-in conductordisposed internally of the envelope with refractory or glass tubes.

These tubes surround the leading-in conductor and at their lower end aresecured to the usual press portion of the envelope either by fusion orby refractory pastes which must be dried out before or during exhaustingof the envelope. Not only is the refractory paste'a source of impuritiesand subject to cracking with resultant electrical leakage, but theutilization of such 40 tubes restricts the leading-in conductor tostraight sections thus making positioning thereof within the envelopeexceedingly difficult.

In addition the construction is of a very fragile nature requiringstrengthening of the seal with the envelope in the event the tube issealed thereto and eliminating the employment of the tube as a supportfor one of the electrodes. Moreover, it is practically impossible tobend or shape the leading-in conductor to any desired configuration.

It is accordingly an object of my present invention to provide anelectric vapor discharge lamp provided with a leading-in conductordisposed internally of the envelope having an insulating sheathing fusedthereto throughout substantially its entire length thus making for anexceptionally rigid construction which is not readily destroyed duringhandling or operation of the lamp.

Another object of my present invention is the 5 method of constructingan electric vapor discharge lamp wherein the leading-in conductor forsupplying electrical energy to one of the electrodes is provided with avitreous sheathing fused thereto throughout its entire length betweenthe 10 oppositely disposed electrodes which may be readily bent andshaped to any desired configuration internally of the envelope.

Another object of my present invention is the provision of an electricvapor discharge lamp 15 provided with a leading-in conductor disposedinternally of the envelope having an insulatingsheathing of vitreousmaterial fused thereto throughout substantially its entire length toform a rigid support for one of the electrodes 20 of the lamp.

A further object of my present invention is the provision of aleading-in conductor for an electric vapor discharge lamp provided witha sheathing of vitreous material fused thereto 25 throughoutsubstantially its entire length.

Still further objects of my present invention will become obvious tothose skilled in the art by reference to the accompanying drawingwherein: 30

Figure 1 is an elevational view in cross-section of an electric vapordischarge lamp constructed in accordance with my present invention.

Fig. 2 is a cross-sectional view taken on the line IIII of Fig. 1, and35 Fig. 3 is a cross-sectional view taken on the line III--III of Fig.l.

Referring now to the drawing in detail, I have shown in Fig. 1 anelectric vapor discharge lamp comprising a vitreous envelope 4, such ashard glass, Pyrex, quartz, or the like capable of withstanding theextremely high temperatures of operation of the lamp, and a quantity ofeasily vaporizable material, such as a globule of mercury 5 is disposedtherein as well as a small quantity of rare gas to facilitate starting,if desired.

A pair of electrodes 6 and l of any suitable type, 4 such for example asa tungsten helix having a coiled coil wound transversely of the helicalwire, 5 are disposed within the envelope 4. The lower electrode 6 issupported by a leading-in conductor 8 sealed into a press portion or thelike 9 of the envelope 4 which extends to the shell portion of astandard type screw base [0 for supplying 55 electrical energy from asuitable commercial source of supply (not shown) to the electrode.

The base I is suitably cemented to the envelope I by a good heatconserving cement, such as an asbestos magnesium oxide admixture andsimilarly cemented to the opposite end of the envelope is a metallic capI! so as to prevent cooling and condensation of the mercury at the endsof the envelope during operation of the lamp. Also disposed adjacent thelower electrode 8 is a starting tip l3 of tungsten which is connected bya sealed-in leading-in conductor ll to one end of a starting resistancei5 embedded within the base l0.

In order to form a rigid support for the upper electrode 1 as well as tosupply electrical energy thereto a leading-in conductor it of suitablemetal, such as molybdenum, is sealed into the portion 9 of the envelopewhich is connected to the center contact point of the base l0 andextends longitudinally of the interior of the envelope where it is benttransversely thereof with its free end contacting the wall of theenvelope. The electrode 1 is secured to this transverse portion of theleading-in conductor It in any suitable manner, such as by welding, at apoint coinciding with the longitudinal axis of the envelope 4 so as tobe positioned opposite the coaxially disposed lower electrode 6.

Also joined to the transverse portion of the leading-in conductor ii atthe point of connection of the electrode 1 therewith is a cross brace I1 extending at right angles to the leading-in conductor 18 as shown moreclearly in Fig. 2 with the ends thereof slightly bent and contacting thewalls of the envelope 4. Thus substantially a four point cross isformed, three points of which contact the walls of the envelope at 90with respect to each other to maintain the electrode 1 in the center ofthe envelope.

However, due to the length of the leading-in conductor I 6longitudinally of the envelope and the fact it does not contact thewalls thereof this would not only allow shifting of the upper electrodeI, but would render the support thereof exceedingly fragile in theabsence of my novel construction.

Accordingly I first form the metallic leadingin conductor II bysurrounding the same while in a straight section with a thin tubing ofvitreous material which may be of the same composition as that of theenvelope. I then heat this tubing to such a temperature as to fuse thesame to the leading-in conductor throughout substantially its entirelength to form an integral sheathing la. The integral sheathedleading-in conductor is then heated at desired locations and bent toform not only the transverse portion previously mentioned, but: also anangular portion shown at l 9 after which the leading-in conductortogether with the electrode I and the cross ltace ll secured thereto isdisposed within the envelope. Due to the fused sheathing i8 being of thesame composition as the envelope it readily fuses with the portion 9 ofthe latter and a perfect seal is formed. Since the leading-in conductorIS with its integral sheathing I8 is bent and formed prior to its fusionwith the envelope it is disposed out of the path of discharge betweenthe oppositely disposed electrodes 6 and I when inserted in theenvelope.

Moreover, a rigid support is thus formed by the leading-in conductor l6for the electrode 1 and the fused sheathing integral therewith, beingfused the entire length of the leading-in conductor between theelectrodes 8 and I, it is not deleteriously affected by the discharge orthe high temperature of the metallic vapor present during operation.After assembly of the various parts the envelope 4 is suitably evacuatedin the usual manner and the globule of mercury 5 together with a raregas inserted prior to sealing ofi at the tip, such as shown at- 20.

The upper cap I2 is then cemented to the upper end and prior toconnection of the base Hi to the envelope the other end of the startingresistance element I5 is connected to the leading-in conductor I6 andthus embedded in the base Ill upon its being cemented to the lower endof the envelope 4 to complete the lamp.

It thus becomes obvious to those skilled in the art that I have providedan electric vapor discharge lamp having a leading-in conductor thereforwhich is provided with a sheathing of vitreous material fused theretothroughout substantially its entire length thus forming a rigidconstruction for supporting at least one of the electrodes of the lampand maintaining the same in a fixed position within the lamp.Furthermore, due to the rigidity of the leading-in conductor with itsintegral sheathing the possibility of disruption or severance thereof ordestruction of the seal with the envelope due to handling of the tube orduring operation thereof is substantially eliminated.

Although I have shown and described one specific embodiment of mypresent invention I do not desire to be limited thereto as various othermodifications of the same may be made without departing from the spirtand scope of the appended claims.

What is claimed is:

1. An electric vapor discharge lamp comprising a vitreous envelopeprovided with a vaporizable material therein and having a press forminga seal, a pair of oppositely disposed electrodes mounted within saidenvelope, and means for supplying electrical energy to said electrodesfor causing a discharge therebetween including a leading-in conductorsealed into said press and offset to position said conductor in closeproximity to the interior surface of said envelope out of the dischargezone between said electrodes and extending in the direction of thelongitudinal axis of said envelope, said leading-in conductor having itsextremity disposed transversely of said envelope and contacting the wallthereof to rigidly fix the position of said leading-in conductor, aninsulated sheathing'fused to said press and to the longitudinallyextending portion of said leading-in conductor to increase the rigiditythereof, one of said electrodes being connected to the transverselypositioned unsheathed portion of said leading-in conductor coaxiallywith respect to the longitudinal axis of said envelope and a baseprovided with a sleeve portion of low heat conductivity surrounding theseal forming press to prevent condensation of the vaporizabie ing in thedirection oi. the longitudinal axis of said envelope, said leading-inconductor having its extremity disposed transversely of said envelopeand contacting the wall thereof, amember normally disposed with respectto the transversely extending portion of said leading-in conductor andhaving its extremities contacting the interior wall of said envelope andcooperating with the transversely extending portion of said leading-inconductor to rigidly flx the position of the latter interiorly of saidenvelope, an insulated sheathing fused to said press and to thelongitudinally extending portion of said leadingin conductor to increasethe rigidity thereof and,

to prevent the occurrence oi a discharge between said leading-inconductor and the electrode disposed adiacent said press, one of saidelectrodes being connected to the transversely positioned unsheathedportionoi' said leading-in conductor at the, intersection of said membernormally disposed with respect to the transversely extending unsheathedportion of said leading-in conductor, and a base provided with a sleeveportion of low heat conductivity surrounding the seal forming press toprevent condensation of the vaporizable' material during operation oisaid lamp, and said sleeve portion being secured to said envelope andextending an appreciable distance longitudinally thereof to form ashield for one of said electrodes to prevent emanation of radiationsfrom said in-.

